1. Field of the Invention
The present invention relates to a robot apparatus, and more specifically, to a robot apparatus which does not need a connecting cable for connecting a robot mechanical unit to a robot controller.
2. Description of the Related Art
Conventionally, a robot mechanical unit is controlled by a robot controller by such an arrangement that the robot mechanical unit is electrically connected to the robot controller disposed externally of the operating area of the robot mechanical unit, for example, on the outside of a safety fence through a connecting cable so that an operation command from the robot control unit is applied to the robot mechanical unit through the connecting cable. For the protection of the connecting cable, the cable is wired through equipment such as a cable duct or a pit defined in a floor on which a robot is installed. The opposite ends of the cable are terminated by connectors which are connected to the connectors of the robot controller and the robot mechanical unit, respectively.
Further, the robot controller is usually installed along a predetermined path for operators formed on the floor on which the robot mechanical unit is installed outside the safety fence disposed to surround the robot mechanical unit. When such a space for installation is not available, a bridge may be installed above the robot mechanical unit to install the robot controller thereon. In any case, the robot mechanical unit is connected through the connecting cable to the robot controller disposed far from it, and equipment is provided to protect the connecting cable.
Since the conventional robot controller is installed at a location far from the robot mechanical unit, the connecting cable is indispensable to the robot controller and a space for installing the connecting cable and equipment for protecting the cable are needed. Further, since the robot controller must be installed externally of the operating area of a robot, a space where the robot controller is installed must be provided.
Further, when facilities of a factory are changed by transferring the robot controller and the like, the robot controller must be disconnected from the robot mechanical unit, which is carried out by removing the connecting cable from the connectors. When the connecting cable is simply removed from the connectors, the connecting cable is left as it is. Since the connecting cable has a large weight per unit length and when there is a distance of e.g. 20 meters between the robot controller and the robot mechanical unit, the weight is as heavy as several tens of kilograms. Thus, when the cable is removed once and reinstalled, the handling of the connecting cable is not easy. Moreover, since equipment for protecting the connecting cable is additionally needed, even if the robot controller or robot mechanical unit is transferred, for example, by 1 meter, it requires a heavy job. Further, when several tens of robots are installed on a manufacturing line of a factory, a job for transferring them is furthermore difficult.